#ifdef a
//字符串逆序存放（字符数组）
#include<stdio.h>
#include<string.h>
void Swap(char* left, char* right) {
    char tmp = *left;
    *left = *right;
    *right = tmp;
    return;
}
void ReverseString(char arr[], int sz) {
    int left = 0;
    int right = sz - 1;
    while (left < right){
        Swap(&arr[left], &arr[right]);
        left++;
        right--;
    }
}
int main() {
    char arr[100] = { 0 };
    scanf("%s", arr);
    int sz = strlen(arr);
    ReverseString(arr, sz);
    getchar();
    printf("%s", arr);
    return 0;
}
#endif
